1. Technical Field
The present invention relates to a computer system, and more particularly, to a computer system which is capable of performing a stable booting operation when power is cut-off and then re-supplied to the computer system, and a method of controlling a standby mode thereof.
2. Related Art
As computer systems have increasingly been used, power consumption has increased accordingly. In this regard, a power management function has been employed in the computer system in order to minimize power consumption. For reduction of power consumption of the computer system and efficient power management, a display operation of a displaying apparatus is in suspension (idle) if no data is input from an input unit for a certain period of time, or a drive operation of a hard disc drive is in suspension (idle) if the hard disc drive makes no access to the computer system for a certain period of time.
A power management function called advanced configuration and power interface (ACPI) specification for managing power of a computer system has been recently proposed, in which the state of the whole computer system is classified into six states.
According to the ACPI, a power management state in a computer system is roughly classified into six steps of sleeping states S0 through S5. The state S0 denotes a normal state (full power on), the states S1 through S4 denote standby states where power consumption of the computer system is stepwise reduced, and the state S5 denotes a soft-off state in which power of the whole system is cut off (full power off). A power supply device for the computer system having the above-described power management function supports an ATX specification including a power supply mechanism comprised of a main power and a standby power. The power supply device supporting the ATX specification always outputs the standby power under the condition that external power is supplied to the computer system. The standby power is supplied to a power management controller of the computer system.
Here, the S3 state of the ACPI is employed to re-use the computer system promptly. In the S3 state, power is not supplied to computer hardware devices except for a system memory and a power management controller composed of volatile memories. The process in which the system proceeds to the S3 state is called a ‘suspend-to-ram’ process during which data in process is stored in the system memory, and the S3 state of the ACPI is stored in the power management controller.
Since a general booting operation is not implemented when the computer system is switched from the S3 state to the normal state, it is possible to re-use the system promptly. However, if power supply to the system memory is cut-off in the ACPI S3 state due to power failure, standby power for maintaining data within the system memory is not supplied to the system memory, thereby causing the data in the volatile system memory to be lost.
If power is re-applied to drive the system again in that state, the basic input output system (BIOS) checks the state S3 in the ACPI of the power management controller, and sends to the system memory a signal requesting data that was being processed. The BIOS is a program for managing data flow between peripheral devices (such as a hard disc, a keyboard, and a mouse) and a computer operating system.
Although the data stored in the system memory is lost due to the cut-off of the power supply, the BIOS continuously requests the data in process from the memory. As a result, the computer system enters a ‘Halt’ state and the ACPI S3 state information in the power management controller is maintained by a complementary metal oxide semiconductor (CMOS) battery, even though the computer system is powered off and on, so that the computer system is unable to operate.
Thus, in order to escape from the ‘Halt’ state, after the computer system is turned off and its body is dismantled, the CMOS battery installed in the main board of the body should be removed to reset the power management controller. This procedure is extremely inconvenient, and it makes it inconvenient to use the computer system.
I have found that the ‘Halt’ state can be extremely inconvenient. Efforts have been made to improve control of systems.
Exemplars of recent efforts in the art include: U.S. Pat. No. 5,845,134 to Arai, entitled SUSPEND/RESUME CONTROL METHOD AND SYSTEM, issued on Dec. 1, 1998, U.S. Pat. No. 6,052,793 to Mermelstein, entitled WAKEUP EVENT RESTORATION AFTER POWER LOSS, issued on Apr. 18, 2000, U.S. Pat. No. 5,721,930 to Kasuga, entitled ELECTRONIC APPARATUS WITH COMPONENT OPERATING STATE CONTROL, issued on Feb. 24, 1998, U.S. Pat. No. 5,551,008 to Saito, entitled METHOD AND SYSTEM FOR RESUMING DATA PROCESSING IN COMPUTER, issued on Aug. 27, 1996, Japanese Patent No. 10-39962 to Clarke et al., entitled COMPUTER SYSTEM, published on Feb. 13, 1998, and Japanese Patent No. 11-194846 to Tsukada et al., entitled COMPUTER SYSTEM AND ITS SYSTEM STATE CONTROL METHOD, issued on Jul. 21, 1999.
While these recent efforts provide advantages, I note that they fail to adequately provide an apparatus or method for efficiently and conveniently preventing the aforementioned “Halt” state.